Crate curds_cron

A library for creating and consuming Cron expressions. It supports some extended syntax.

Overview

Each expression consists of five fields, space separated, representing different parts of the day in the following order:

• Minute
• Hour
• Day of Month
• Month
• Day of Week

Each field consists of some number of values, comma separated, indicating when the expression is a match. In addition to the regular:

• Single value
• Inclusive range of values
• Wildcard

Expressions can also include:

• Step ranges
• Weekday nearest to Day of Month
• Last Day of Month (with or without an offset)
• Nth Day of Week
• Last Day of Week

Additionally, Month and Day of Week values can be represented numerically or with a three-letter abbreviation (JAN -> 01 or wed -> 3, respectively).

Examples

An expression that is always a match.

use chrono::{DateTime, Utc};
use curds_cron::CronExpression;
let anytime = "* * * * *".parse::<CronExpression>()?;
assert_eq!(true, anytime.is_match(&Utc::now()));

An expression that matches on the last day of February, April, or December.

use chrono::{DateTime, Utc};
use curds_cron::CronExpression;
let end_of_months = "* * L 2,APR,dec *".parse::<CronExpression>()?;
assert_eq!(true, end_of_months.is_match(&"2021-04-30T00:00:00Z".parse::<DateTime<Utc>>()?));
assert_eq!(false, end_of_months.is_match(&"2021-12-30T00:00:00Z".parse::<DateTime<Utc>>()?));

An expression that matches at noon on Saturdays.

use chrono::{DateTime, Utc};
use curds_cron::CronExpression;
let saturday_noon = "0 12 * * SAT".parse::<CronExpression>()?;
assert_eq!(true, saturday_noon.is_match(&"2021-04-10T12:00:00Z".parse::<DateTime<Utc>>()?));
assert_eq!(false, saturday_noon.is_match(&"2021-04-11T12:00:00Z".parse::<DateTime<Utc>>()?));

An expression that matches at the top of each hour between 8AM and 5PM on the last Friday of the month.

use chrono::{DateTime, Utc};
use curds_cron::CronExpression;
let last_friday = "0 8-17 * * friL".parse::<CronExpression>()?;
assert_eq!(false, last_friday.is_match(&"2021-04-23T12:00:00Z".parse::<DateTime<Utc>>()?));
assert_eq!(true, last_friday.is_match(&"2021-04-30T12:00:00Z".parse::<DateTime<Utc>>()?));

An expression that matches on the third Monday of January.

use chrono::{DateTime, Utc};
use curds_cron::CronExpression;
let third_monday = "* * * Jan Mon#3".parse::<CronExpression>()?;
assert_eq!(false, third_monday.is_match(&"2021-01-11T00:00:00Z".parse::<DateTime<Utc>>()?));
assert_eq!(true, third_monday.is_match(&"2021-01-18T00:00:00Z".parse::<DateTime<Utc>>()?));

An expression that matches on Wednesdays between the 10th and 20th.

use chrono::{DateTime, Utc};
use curds_cron::CronExpression;
let middle_weds = "* * 10-20 * wed".parse::<CronExpression>()?;
assert_eq!(false, middle_weds.is_match(&"2021-01-12T00:00:00Z".parse::<DateTime<Utc>>()?));
assert_eq!(true, middle_weds.is_match(&"2021-01-13T00:00:00Z".parse::<DateTime<Utc>>()?));

An expression that matches every fifth minute five days before the last day of the month.

use chrono::{DateTime, Utc};
use curds_cron::CronExpression;
let fifths = "*/5 * L-5 * *".parse::<CronExpression>()?;
assert_eq!(false, fifths.is_match(&"2021-04-25T00:03:00Z".parse::<DateTime<Utc>>()?));
assert_eq!(true, fifths.is_match(&"2021-04-25T00:05:00Z".parse::<DateTime<Utc>>()?));

Structs

CronExpression

An representation of a Cron Expression.

Enums

CronDatePart	An enum to represent the various parts of a DateTime against which a CronExpression can match.
CronParsingError	An enum covering the possible failures when parsing a CronExpression.